In the framework of the underground
experiments at the Gran Sasso laboratory, a high
energy cosmic ray generator has been developed.
This is based on the FLUKA Monte Carlo code and it
is primarily dedicated to the analysis of high energy
muons detected underground. For this purpose the
code simulates both the air shower development and
the muon transport in the rock.
We analyze the prediction for the charge ratio of
underground muons, with the aim of investigating
some features of the high energy particle production
model. This measurement is particularly sensitive to
the pi/K ratio of secondary mesons produced in the
proton-Air and Nucleus-Air collisions.
We analyze the possible dependence of charge ratio
on the event multiplicity and primary composition
model. We also compare our predictions with published
experimental results.

In the framework of the underground
experiments at the Gran Sasso laboratory, a high
energy cosmic ray generator has been developed.
This is based on the FLUKA Monte Carlo code and it
is primarily dedicated to the analysis of high energy
muons detected underground. For this purpose the
code simulates both the air shower development and
the muon transport in the rock.
We analyze the prediction for the charge ratio of
underground muons, with the aim of investigating
some features of the high energy particle production
model. This measurement is particularly sensitive to
the pi/K ratio of secondary mesons produced in the
proton-Air and Nucleus-Air collisions.
We analyze the possible dependence of charge ratio
on the event multiplicity and primary composition
model. We also compare our predictions with published
experimental results.